Federal water monitoring extends to thousands of public water systems, and in Houston, Texas, that tracking has turned up Arsenic — the detection is logged in the EPA compliance record and reflects samples collected under routine Safe Drinking Water Act reporting requirements.

Data: EPA SDWIS, CCR Reports, ECHO Last verified: 2026-05-14

Arsenic in Houston Tap Water

Arsenic has been detected in Houston, Texas drinking water at a maximum level of 9.9 ppb — below the EPA MCL of 10 ppb.

This analysis covers 3,195,329 residents across 190 ZIP codes in Houston.

Houston's overall water quality grade is A (87/100).

Is Arsenic in Houston Water Safe?

Arsenic was detected in Houston water but currently falls within EPA limits. However, some health organizations argue the EPA MCL may not be protective enough.

If you are concerned, a reverse osmosis filter can reduce arsenic levels further.

Arsenic Levels by ZIP Code

Average arsenic level across Houston: 9.9 ppb

Health Effects of Arsenic

• Increased risk of skin, bladder, lung, and kidney cancer
• Cardiovascular disease and type 2 diabetes
• Skin changes (darkening, thickening, lesions)
• Developmental effects in children exposed in utero

Health risk severity: High. Governed by the Arsenic Rule (2006).

How Arsenic Gets Into Drinking Water

• Natural deposits in rock and soil (especially in western U.S.)
• Runoff from orchards and glass/electronics production
• Historical use of arsenic-based pesticides
• Well water in areas with arsenic-rich geology

What to Do About Arsenic in Houston Water

1. Install a reverse osmosis (RO) system certified under NSF 58
2. Adsorptive media filters (iron-based) can also reduce arsenic
3. Have well water tested if on a private supply
4. Boiling water does NOT remove arsenic — it concentrates it

Look for filters certified under NSF 53 / NSF 58 for arsenic removal.

Related

• Arsenic — National Overview
• Arsenic in Texas
• Texas Water Quality
• Houston Water Quality
• Check Your ZIP Code